Method of forming a well in light bulbs



Dec. 17, 1957 z. SOLTYSIK 2,816,399

' METHOD OF FORMING A WELL IN LIGHT BULBS Filed Jun 9. 1953 INVENTOR. %w

A T TORNE Y nie StatesPatent O METHOD or FoaMING A WELL IN LIGHT BULBS Zeno Soltysik, Chicago, 111. Application June 9, 1953, Serial No. 360,437

2 Claims. or. 49-78) This invention relates to a method of forming a surface depression or well in the globe of a light bulb and to the well-equipped bulbs formed thereby.

There are a number of materials that vaporize readily upon the application of heat and the vapors from a number of such materials may be desirably dispersed within a room space. Examples of such materials the vapors from which may be dispersed within a room, are those having a pleasing fragrance such as perfumes, incense, etc., and also insecticidal materials, the vapors being employed to kill flies, mosquitoes, and other insects and pests. The amount of heat required to vaporize these materials (which may be initially in powder, tablet, or liquid form) is not great and could be readily supplied by the heat dissipated by a lighted or burning light bulb. A light bulb suitably equipped with a well providing a reservoir for heatvaporizable material would provide a convenient structure for supporting and vaporizing such material, particularly because the heat generated by a light bulb is normally wasted and because of the ready availability of bulbs and receptacles therefor.

It is therefore an object of this invention to provide a conventional light bulb with a small depression or well in the globe thereof forming a reservoir adapted to receive a material therein. Another object of the invention is to provide a method for forming a depression or well in the glass globe of a conventional light bulb after the bulb is a finished article already usable for lighting purposes. Still another object is in providing a frosted light bulb having a well in the globe thereof suitable for receiving a material that is vaporizable 'by the heat of the lighted bulb. A further object is in the provision of a method for forming a depression in a wall of a relatively thin-walled closed member having a reduced interior pressure such as the globe of a finshed conventional light bulb by the application of a controlled flarne to the area of the wall to be depressed, whereby the area of the wall is softened and the reduced pressure within the member and higher pressure on the outside thereof are operative to force the softened wall area inwardly with the result that a well is provided in the wall. Yet a further object is in providing a method for forming a well, as described above, but wherein a rod-like member is pressed with a slight pressure against the heated and softened area of the wall to push the same inwardly and thereby form a well. Still a further object is to provide a conventional finished, frosted globe light bulb with a depression or well in the globe thereof, the depressed area of the globe being clear, whereby the well area is strengthened. Additional objects and advantages will appear as the specification proceeds.

Embodiments of the invention are illustrated in the accompanying drawing, in which Fig. 1 is a side View in elevation and with portion shown in' section of a light bulb having a flame applied to an area of the globe; Fig. 2 is a side view in elevation of a light bulb having a well formed therein and in which 2,816,399 Patented Dec. 17, 1957 portions of the globe are shown in section; Fig. 3 is a view similar to that of Fig. 2, but showing the well filled with a liquid; and Fig. 4 is a side view in elevation with portions being shown in section similar to that of Fig. 1, but showing a modified form of the invention; and Fig. 5 is a view similar to Fig. 4 but showing a further modification.

In the method of the invention, a small depression or well isformed in a wall of a thin-walled member that is closed and has an interior pressure that is at least slightly less than the exterior pressure surrounding the member. As a specific illustration, such a thin-Walled member is shown in the form of a light bulb 10. The light bulb 10 is conventional in all respects and is equipped with a glass globe 11 having secured to the lower end thereof a threaded socket 12 that may be threadedly received within a suitable electric outlet receptacle. The globe 11, in the case of a light bulb, is made of glass and is relatively thin-walled. The glass may be frosted, as is illustrated and designated by the numeral 13 in the sectional portions of Figs. 1 through 4.

For purposes of convenience in carrying out the method, the light bulb 10 is shown in Figs. 1 and 4 mounted in a chuck 14 that is equipped at one end with a familiar receptacle 15 adapted to receive the threaded end of the bulb 10 therein. The chuck 14 will be rotated by any suitable and well-known means, and since such drive means are well known they are not illustrated and will not be further described. Preferably, the chuck 14 is rotated in a counterclockwise direction so that the light bulb 10 will not be screwed from the receptacle 15 during rotation thereof.

To form the recess or well 16 in the globe 11 of the light bulb, an area of the globe that is to be depressed and to thereby form the depression 16 is heated. I prefer to heat the globe portion by means of a flame 17 that may be produced by igniting a gas and air mixture flowing through a nozzle 19. Any combustible gas and air mixture may be used, and instead of air oxygen may be employed if this is desired. For example, acetylene and oxygen may be mixed and ignited to provide the flame 17. The flame 17 is brought into contact with the glass globe 11 and the area of the globe that the flame impinges upon is thereby heated. The globe area being heated is raised to the softening temperature of the glass and the partial vacuum within the globe 11 and the atmospheric pressure on the outside of the globe are effective to force the heated portion of the globe in wardly and the well 16 is thereby formed.

If the well or small depression 16 is to have a small diameter, the flame 17 is held directly against the portion of the globe that is to be depressed. The flame is held against the globe until the area in contact with the flame softens and is drawn inwardly by the action of the atmospheric pressure on the outside of the globe in combination with the reduced pressure within the globe. In the event that a larger depression or well 16 is desired, either the flame 17 may be moved through a circle about the center point of the depression to heat and soften a larger surface area of the globe 11 or, alternatively, as is illustrated in Fig. l, the flame 17 and nozzle 19 may be held stationary and angularly disposed relative to the globe 11 so that the flame 17 impinges upon the globe at a point slightly spaced from the center of the recess or well 16. The globe 11 is then rotated and the flame 17 subscribes a circle about the center of the well 16. As

that is to form the well 16 that the flame 17 be withdrawn from contact with the globe 11 at the time the heated and softened globe area is being drawn inwardly. The proper time can be determined by visual observation. Preferably, at the moment the heated portion of the globe starts to move inwardly, the flame is withdrawn from the globe.

It is also important during the heating of the globe area that the entire globe, apart from the area being heated, remain relatively cool. If the entire globe is heated the gases within the partially evacuated globe are heated and expand and the glass globe will explode. It is important then to concentrate the heat, whether it is provided by a flame 17 or otherwise, in the particular area that is to be depressed and provide the Well 16.

In the modified form of the method illustrated in Fig. 4, the bulb is supported in a chuck 14 in a manner identical with that described with reference to Fig. l. The flame 17 is provided by the combustion of gases flowing through the nozzle 19 and the flame impinges upon the glass globe 11 of the bulb and thereby heats the same. In addition to the use of the flame for heating the globe, a rod 20 having a slightly curved end 21, is pressed against the heated portion of the globe with a very slight pressure to force the same inwardly after it has been heated to the softening point, and thereby provide the well 16a. This method has been found desirable where it is required to produce a recess of greater diameter than those that can be conveniently produced by the flame method alone. In the modified arrangement, the nozzle 19 is adjusted so that the flame 17 issuing therefrom impinges upon the glass globe 11 of the bulb at a point spaced from the center of the well 16a. As the bulb is rotated by the chuck 14 the flame 17 subscribes a circle about the center of the recess 16a. The area of the globe having the flame impinging thereon is heated to the softening temperature of the glass and the rod 269 is moved against the softened globe area and the slight pressure exerted thereby against the softened glass forces it inwardly, and the recess or well is thereby formed. Preferably, the rod end 21 engages the softened glass at a point spaced from the center of the recess 16a and it, too, subscribes an are or circle about the center of the well. The pressure is effective to push the softened globe portion inwardly and to form a well that has a greater diameter than the wells conveniently formed by the flame method alone. Also, when the rod 20 is employed, it is not essential that the pressure within the globe be less than the exterior pressure about the globe. The rod 20 may be formed of numerous materials that are not affected adversely by the heat from the flame 17. I have found that both metal, such as steel, and carbon rods may be employed successfully.

I have found that where the light bulb 10 is of the type having a frosted globe, that the heated area of the globe that is drawn inwardly to provide the well is substantially clear after the well is formed therein. This is desirable because it has the effect of strengthening the glass that provides the actual recess. The reason for this, it is believed, is that when a glass globe of a light bulb is treated to frost the same, the interior of the globe is subjected to an acid bath such as hydrofluoric acid, and the acid is effective to eat away surface portions of the globe and thereby produce a plurality of fine scratches or etches in the globe that substantially weaken the same. When the globe is then heated to the softening point thereof in the area that provides the well, the softened glass flows slightly and fills the scratches or etches and the continuous unmarred glass portion thereby formed is stronger than the initial globe. This is important because normally the sunken area providing the well would be somewhat weakened because of the stretching of the glass after it is drawn inwardly.

Figs. 2 and 3 show a light bulb 16) having a recess 16 formed therein and in which is inserted initially a tablet 21a that, when heated, melts to provide a liquid body 22,

as is illustrated in Fig. 3. A liquid might be placed within the well 16 initially or a powder might be placed there in instead of the tablet 21a. In any event, the material Will be liquefied by the heat from the burning bulb 10 and the vapors from the liquid will be dispersed throughout a room space. Preferably, the tablet 21a is formed of an insecticidal material so that the vapors dissipated within a room are effective to destroy insects, etc.

In the modification of the invention shown in Fig. 5, a. pair of controls 19 are oriented so that the flames 1'7 thereof are directed inwardly toward the end of the glass globe 11 of the light bulb adjacent the peripheral edges of the well to be formed therein. A red 22 having an enlarged end portion 23 is moved, after the portion of the globe to have the well formed therein is heated, toward the globe and against the softened glass portion thereof. The enlarged end 23 of the rod 22 pushes the softened glass inwardly and the well 16b is formed therein. This modification of the invention has been used successfully to form wells of large diameter in the glass globes of light bulbs. The impinging of the flame 17 upon the glass adjacent the periphery of the recess and the subsequent moving of the rod thereagainst appears to roll the glass at the peripheral edge of the recess and no appreciable stretching or thinning of the glass at this area is apparent. Excellent results have also been achieved where one of the flames has been directed toward the center of the recess and the other flame against the glass globe adjacent the periphery of the recess to be formed therein. It should be understood that relative movement between the bulb and flames and rod takes place during the well forming operation. ireferably the bulb is supported within a chuck as is illustrated in Figs. 1. and 4. In this modification and in the other embodiments set out herein the glass globe could be heated by any suitable means other than the preferred form that is illustrated.

1 have in a number of experiments working with conventional light bulbs, and that have been of 25, 40, 60, 75 and watt capacity and all 128 volt bulbs, produced recesses or Wells 16 and M by both the flame method alone and by the flame and rod method, as shown in Fig. 4, that have varied in diameter from A to 1% inches.

While in the foregoing specification embodiments of the invention have been set out in considerable detail for purposes of illustration, it is understood that changes in these details may be made without departing from the spirit and teachings of this invention.

I claim:

1. In a method of forming a recess in the sealed glass envelope of a light bulb having the interior surface thereof etched to frost the same, the steps of impinging an open flame on a restricted area of said glass envelope, maintaining said open flame in impingement thereon until the frosting commences to disappear in the substantial clearing of the glass envelope of its etching in that area, and pressing a forming tool against the heated area of the glass envelope to depress the same and thereby form a recess therein, that portion of the glass envelope stretched in the formation of said recess and otherwise weakened thereby being strengthened by the minimi2a tion of said etching.

2. in a method of forming a recess in the sealed glass envelope of a light bulb having the interior surface thereof etched to frost the same, the steps of impinging an open flame on a restricted area of said glass envelope, maintaining said open flame in impingement thereon to elevate the temperature of such area until a minimization of the frosting and clearing thereof occurs, and applying an external force against the heated area to depress the same and thereby form a recess therein.

References Cited in the file of this patent 2,123,957

UNITED STATES PATENTS 793,211 McDonnell June 27, 1905 1,535,486 Lundy Apr. 28, 1925 5 1,875,819 Naruse Sept. 6, 1932 194318 1,963,008 Weeks June 12, 1934 171618 1,981,330 Rivier Nov. 20, 1934 6 Orth July 19, 1938 Hahn et a1. Feb. 7, 1939 Stewart June 27, 1950 FOREIGN PATENTS Great Britain Jan. 3, 1924 Switzerland Nov. 16, 1934 

